This section presents
information about the sources used for the data listed for each airgun
in the collection. Much of this information was obtained from
measurements made using the equipment shown below. The pellet/BB trap is
my own design and uses ballistic curtains with a steel back plate. The
backstop is made of 1050 denier ballistic nylon (used in "bullet-proof"
vests).

Measurement Setup
Ready for Testing

Backstop and Pellet Trap

Instruments Used for Measuring Airgun Properties

Airgun Data Sheet
(click image for pdf copy)

Recommended Pellet or BB:Airguns are pretty
particular about the kind of ammunition they like. Performance can vary
quite a bit from one brand of pellet or BB to another in the same gun. I
have measured the basic parameters of a large number of pellets and BBs suitable
for air pistols and tabulated the results in a document you can view by
clicking here. Each airgun in this collection was tested with a variety
of appropriate pellets (usually wadcutter) or BBs (lead or steel) and the one
that gave the best performance (good grouping and least jamming) is
listed as the "Recommended Pellet or BB". This is also the
pellet or BB that is then used for velocity testing.

Weight (lb)/Length (in):The weight of each airgun is
listed in the "Info" section and was
measured to the nearest 0.1 ounce (converted to nearest 0.1 lb)
using a
digital postage scale. Length was measured from a
plane perpendicular to the muzzle to the farthest point on the
gun.

Barrel Length (in)/Material/Rifled:When possible, barrel length is measured by inserting a cleaning rod
down the barrel until it reaches the end of the barrel. The rod
is marked, withdrawn, and the length measured with a ruler. In a
few cases, barrel length information was taken from
the manufacturer's literature due to the difficulty in accurately measuring the length of the barrel
without disassembling the gun. The presence of rifling was determined by simple
visual inspection.

Trigger Action:In single-action mode, pulling the trigger simply releases
the hammer. The hammer is cocked in a separate step, either
manually or automatically by gas expelled in the previous firing
operation. In double-action mode, pulling the trigger cocks the
hammer, brings a pellet into firing position, and then releases
the hammer. In most cases, trigger action was determined
by firing the gun and observing how the action operated.

Trigger Pull (lbs)/Adjustable:Trigger pull was measured to the nearest 0.1
lb using a
Lyman digital trigger pull gauge. The value reported
is the average of five measurements. Trigger pull was measured
for both single and double action firing. For those guns that
must be charged with CO2
in order for the trigger to function (e.g. Schimel GP-22), a fresh CO2
cylinder was loaded. Guns that use a removable ammo magazine had
the magazine installed when testing trigger pull since part of
the trigger's action is to rotate the magazine.

Velocity (fps): The
muzzle velocities listed in the "Info" section are from the
manufacturer's literature. Velocities listed in the
"Performance" section were measured using a
Shooting Chrony Beta Master
chronograph (replaced in 2010 with CED M2 chronograph) with the indoor light kit.
The pellet or BB used for velocity testing was the one that
proved to be the most accurate of all that were tested. The far end of the
chronograph was positioned at a distance of 3 feet from the
muzzle. The average velocity reported was determined from a 10
shot string. The first shot in the string was fired with a fresh
CO2 cylinder. Shots
were fired about 15-20 seconds apart. Guns that fire both SA and
DA were tested in SA mode only.
Click here for information discussing the relationship
between velocity and temperature.
Click here to download an Excel spreadsheet for calculating
velocity statistics and muzzle energy (fpe).

Note: In January
2010, the Shooting Chrony chronograph was replaced with a
CED M2 chronograph with the infrared screen upgrade.

2005-2010

CED M2: 2010-present

Sound Level (dB): The peak sound pressure level produced by the muzzle
blast was measured with an
Ivie IE-33 SPL meter
and calibrated microphone. The SPL was
measured with "A" weighting and peak readings were recorded for
the same 10 shot string used to measure velocities. The
microphone was positioned three feet from the muzzle and
oriented at 45º to the line of fire. Only the highest
SPL is reported. A difference of 6 dB in SPL is a perceived
doubling of the sound level. For example, a muzzle blast of 101
dB will seem twice as loud as a blast of 95 dB. Ambient sound level was
approximately 35 dB.

Pellet Holder Thickness (in): This measurement indicates the thickness (in
inches) of the clips or magazines that hold pellets in
repeaters. This measurement is important when trying to match
pellets with air guns to avoid jams that result when a pellet is
longer than the thickness of the clip.

Temperature and Humidity:
Environmental air temperatures were recorded to the nearest 1 ºF
using an
Acu-Rite digital thermometer. The vapor pressure of
liquid CO2 changes
with temperature. Liquid CO2
vaporizes with each shot causing the temperature of the contents
of the CO2 cylinder
to drop. Therefore, after the first shot, the temperature of the
CO2 in the cylinder
will be lower than the surrounding air temperature. The first
shot fired from a fresh CO2
cylinder will have the highest velocity and this number is
reported as part of the performance data. It is standard
practice to report the temperature of velocity tests as the air
temperature.
Click here for information discussing the relationship
between velocity and temperature.

Grouping:
The precision of each airgun (commonly but incorrectly referred
to as "accuracy" by most shooters) was tested by firing a series
of shots into a paper target from a bench rest at a distance of
15 feet. These tests were performed using the pellet or BB that
was previously determined to work best with the gun under test.
A
Cabela's digital caliper, with the zero offset by 0.177" or 0.22"
(one pellet diameter), was
used to determine the maximum outside edge-to-edge distance of
holes in the target. The reading on the caliper is the
C-T-C (center-to-center) spread of the group.

Manufactured Dates:
The beginning and ending dates for the manufacture of each airgun
were obtained from a variety of sources including the
Blue Book
of Airguns,
Crosman,
Daisy, and other
manufacturer's Web sites, books on the
history of airguns, and industry news reports. There is no
industry standard for reporting manufacturing dates with some sources
using company announcements of new products and other sources using the
dates a gun was released to distribution channels.The
same holds true for the dates of discontinuation, with some
sources using the date the manufacturer actually stopped making
the gun and others using the date the gun was pulled from
marketing channels. These dates can, and often do, differ by up
to a year or two.

Condition:The condition of each airgun is reported
according to the guidelines described in the Blue Book of
Airguns (6th Ed.).
Click here for a description of the grading system. This
grading system is specific to airguns and takes into account the
fact that, even when new, airguns don't often have the same
level of fit and finish that most firearms have.